This section provides background information related to the present disclosure which is not necessarily prior art.
Chassis for utility vehicles are generally manufactured on the basis of a continuous ladder frame. Such a ladder frame consists of two longitudinal members which are formed, for example, as C-shaped profiled elements and which are connected together by a plurality of crossmembers. Generally the longitudinal members are screwed or riveted to the crossmembers. Different vehicle components are attached to the frame, such as for example the front and rear axles, the drive units, the driver's cab, the transport structure or semi-trailer coupling, the fuel tank, the battery housing, as well as the exhaust gas system. It is desirable to provide a modular design in order to be able to apply one type of chassis to different vehicle variants or drive systems in a flexible manner.
Chassis of the ladder frame design are sufficiently stable, but have a relatively high dead weight. This problem of a high dead weight is exacerbated as, due to statutory emission requirements which are becoming increasingly strict, additional exhaust gas treatment components such as for example catalytic converters or urea tanks have to be provided on the vehicle. Further factors increasing the weight are the higher proportion of electronics, in terms of sensor systems and actuating systems, greater comfort requirements and the use of alternative fuels or drive concepts, wherein hybrid drives, in particular, may be cited as an example thereof. A high dead weight is associated with a lower payload, increased fuel consumption and, as a result, with undesirable additional costs and greater pollution.
A chassis of modular construction for utility vehicles is disclosed in DE 102009012350A1, said chassis achieving a reduction in weight relative to conventional chassis whilst maintaining the usual properties of rigidity and strength, wherein the central subassembly is configured as a box-shaped hollow profile made of sheet metal formed parts and the longitudinal members of the front and rear subassemblies are at least partially configured from closed profiled parts and at least one of the front and rear subassemblies is releasably attached to the central subassembly.
The inner hollow space of the box structure of the central subassembly may be used, for example, for the protected accommodation of parts of the drive system, the supply tank and/or the exhaust gas system of the utility vehicle. As one of the connecting points between the individual subassemblies is releasable, the vehicle parts to be accommodated may be easily inserted when assembling the utility vehicle. For connecting a conventional utility vehicle frame to an independent wheel suspension and for fastening attachments and an underride protection system thereto, a plurality of heavy and complex brackets are generally required. In order to avoid problems of vibration and rigidity in this design, the frame itself has to be designed to be very rigid and thus heavy. Therefore, at the present time, chassis with independent wheel suspension are hardly used in spite of the advantages of independent wheel suspension.
A suspension subframe for an independent wheel suspension for a utility vehicle is disclosed in EP1902873 A1, said suspension subframe having retaining elements for attaching the suspension device and the transverse control arm, and being able to be attached to the frame longitudinal members of the vehicle. The retaining elements are designed in this case as pressed parts or welded assemblies and, due to the attachment thereof to the conventional vehicle longitudinal members, the total weight tends to be increased by the construction.